Seeing how Spock's my favorite Trek character, I went with the movies since he wouldn't have been a regular in Phase II. Ideally, I would have loved ST:TMP as the 2-hour premiere of Phase II followed by the series which included Spock exploring his newfound acceptance of emotions. They could have left Xon in as a backup science officer and used him to show the contrast between Xon as a Vulcan and Spock as accepting his human side more.